Refrigeration



Dec. 22, 1931. I c, PLQEGER 7 1,838,040

REFRIGERATION Filed Oct. 7; 1930 Z INVENTOR Ciqde E. Ploeqer. BY

I r \A. 1

ATTORNEY Patented Eats. 22, 1&3!

ITED STATES CLYDE E. PLOEGER, F EVANSVILLE, INDIANA, ASSIGNOR TO SERVEL INQ, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE BMRIGERATION Application filed October 7, 1930. Serial No. 486,938.

This invention relates to refrigerating systems of the compressor-condenser-expander type and more particularly to ameans for returning lubricant from the refrigerating element or evaporator to the compressor.

In some refrigerating systems lubrication of the compressor is accomplished by using a so-called working fluid which consists of a refrigerant and a lubricant which combine into a uniform mixture. In other refrigerating systems a separate source of lubricant is provided for the compressor, but some of the lubricant mixes with the compressed refrigerant and passes through the condenser and into the evaporator. Due to the relatively less volatile nature of lubricants as compared to refrigerants, the latter pass from the evaporator back to the compressor through the vapor suction line while the lubricant remains in the evaporator. In time, the accumulation of lubricant in the evaporator will seriously impair the efficiency of the system, wherefore in both of these systems it is necessary to provide some means for returning the lubricant from the evaporator to the compressor. A very convenient method of doing this is to introduce the lubricant from the evaporator into the vapor suction line where it is drawn along with the refrigerant vapor back to the compressor.

This invention contemplates a simple but positive means for effecting the transfer of lubricant into the vapor suction line where it can be drawn back into the compressor. More specifically this invention contemplates the combination of a capillary device as, for instance, a wick and a lubricant ejector for transferring lubricant or a mixture of lubricant and refrigerant from the evaporator into the vapor suction line to the compressor.

This invention will be more readily understoood by reference to the following description taken in connection with the accompanying drawings in which like reference char acters indicate like parts.

Fig. 1 is a vertical section of an evaporator of the flooded type and a lubricant return means contemplated by this invention;

Fig. 2, a top plan view of the evaporator in Fig. 1; and

Fig. 3, an end view of the evaporator. An evaporator of any desired construction has a portion 11 thereof threaded at 12 or otherwise provided with means to connect with the lubricant ejector housing 13. Such housing is provided with a chamber 1 1 in communication with both the liquid and vapor space in the evaporator 10 and a chamber 15 is separated from chamber 14: by a partition 16. The partition 16 extends upwardly and has a small opening 17 forming communication between the two chambers far enough above the normal liquid level in evaporator lO and chamber 14 to prevent any liquid from boiling over into chamber 15 when evaporation takes place.

The vapor suction line 18 from the com pressor is connected in any convenient manner to the housing 13 at 19 and communicates with the upper part of chamber 15 through passages 20 and 21 in the lubricant ejector housing 13. Passages 22 and 23 drilled in the housing 13 connect the lower part of chamber 15 with passage 20. With this construction the vapor suction line 18 communicates with both the upper and the lower part of chamber 15.

A suitable capillary device such as wick 24: extends from a point below the liquid level in the evaporator over the top of partition 16 and extends to a point near the bottom of chamber 15. Any suitable means such as spring clip 25 may be used for holding the wick 24 in position.

Refrigerant is supplied to the evaporator and the quantity of such refrigerant in the evaporator is controlled in any desired manner, for example, the refrigerant may be supplied through conduit 26 in which there is a suitable control means such as capillary tube 27 which is given suiiicient length by forming it into coils E28 and 29.

In operation, liquid consisting of a mixture of refrigerant and lubricant in the evaporator 10 is carried by the wick 24 over the top of partition 16 and into chamber 15. The part of the wick above the liquid level in the evaporator and especially the portion over the top of partition 16 is in a region of reduced pressure due to the removal of re frigerantvapor by the suction of the compres sor through line 18. Due to this reduced pressure and the greatly increased surface presented by the wick, the refrigerant will evaporateout of the liqpid passing through the wick leaving the lu ricant which is of a less volatile nature to be deposited in cham' ber 15 from which it is sucked up through passages 22 and 23 by the ejector action of the refrigerant vapor being sucked through passage 21 and is returned to the compressor along with the refrigerant vapor through the suction line 18.

If a lubricant is used which does not mix with the refrigerant but stratifies and assumes its own level in the evaporator, it is only necessary to extend the end of the wick 24 into the lubricant stratum. If the lubricant is of such a specific gravity that the refrigerant stratum is uppermost, the wick may be suitably encased from a point above the normal liquid level to a point within the lubricant stratum to exclude refrigerant. With such an arrangement only lubricant will be conveyed by the wick into chamber 15 to be sucked up by the compressor.

When the compressor ceases to function there is a consequent cessation of the flow of the vaporized refrigerant back to the compressor and this causes an equalization in pressure between the chamber 14 and the suction line. Consequently there is no difference in pressure to eflect the feeding of oil from the chamber into the suction line. Due to the capillary attraction of the wick, the lubricant continues to be siphoned over the partition into the chamber 14 until such time as the lubricant within said chamber reaches the level of the mixture in the evaporator, at which time the siphoning action of the wick ceases.

On account of the ejector housing 13 which contains the lubricant chamber 14 being disposed without or exteriorly of the evaporator, it is surrounded by air which is warmer than the refrigerating medium and thus the chamber 14 is maintained at a higher temperature than the body of the evaporator proper. This higher temperature assists in evaporation of liquid refrigerant and reduces to a minimum any such refrigerant entrained with the oil after its assage over the bafile or partition between t e chambers 14 and 15.

While for purposes of illustration the ejector housing has been shown and described as attached to the evaporator, the invention is not intended to be so limited, but it will be understood that the invention contem lates the insertion of the ejector housing within the suction line in spaced relation to the evaporator in which position of course it will be necessary to increase the length of the wick which carries over the lubricant and instead of merely passing into the suction line at a point above the baflle or partition it will extend for a substantial distance through or along the suction line.

It will be obvious to those skilled in the art that various other changes may be made in the construction and arrangement without departing from the spirit of the invention and therefore the invention is not limited to what is shown in the drawings and described in the specification but only as indicated in the appended claims.

I claim:

1. In a refrigerating system, means for returning lubricant from the evaporator to the compressor comprising an ejector housing mounted exteriorly of the evaporator where it is exposed to the warm atmosphere outside the evaporator, a lubricant collecting chamber within said housing, a suction line communicating with the upper portion of said lubricant chamber, and a wick for transferring lubricant from the evaporator into said chamber.

2. In a refrigerating system comprising an evaporator, a compressor, a suction line between the evaporator and the compressor, means for returning lubricant from the evaporator to the compressor comprising a housing inserted in said suction line and provided with a lubricant chamber communicating at its upper portion by means of the suction line with the evaporator and compressor and at its lower portion with the suction line, and means for transferring lubricant from the evaporator into said chamber.

3. In a refrigerating system of the compressor-condenser-expander type, lubricant return means in the vapor suction line comprising a chamber in open communication with the vapor space in the evaporator, a wick extending from below the normal liquid level in the evaporator into said chamber, and a conduit independent of the suction line between the suction line and the lower ortion of said chamber for withdrawing lu ricant from said chamber.

4. In a refrigerating system of the compressor-condenser-expander type, lubricant return means in the vapor suction line comprising a chamber in open communication with the vapor space in the evaporator, said chamber extending above and below the nor- --'mal liquid level in the evaporator, a wick extending from below the normal liquid level in the evaporator into said chamber and a conduit independent of the suction line between the suction line and the lower portionof said chamber for withdrawing the lubricant from said chamber.

5. In a refrigerating system of the compressor-condenser-expander type, lubricant return means in the vapor suction line comprising a chamber with its upper portion above the normal liquid level in the evaporator and communicating with the vapor space in said evaporator, a wick extending from below the normal liquid level in the evaporator into said chamber and a conduit independent of the suction line between the suction line and the lower portion of said chamber for withdrawing lubricant from said chamber.

6. In a refrigerating system, an evaporator, means for maintaining a substantially constant quantity of liquid in said evaporator, a chamber outside of said evaporator communicating from its upper portion with the evaporator above the normal liquidlevel, a wick extending from the lower part of said chamber into said evaporator below the normal liquid level, a suction line communicating with the upper part of said chamber, and a connection from the lower part of said chamber to said suction line.

7. In a refrigerating system, an eva orator of the fiooded type, a chamber outslde of said evaporator communicating from its upper portion with the vapor space in the evaporator, capillary means extending from said chamber into said evaporator below the normal liquid level therein, a suction line communicating with said chamber, and an ejector tube extending from the lower part of said chamber into the suction line.

8. In a refrigerating system, an evaporator, a fluid tight vessel, a conduit connecting the upper part of said vessel with the vapor space of the evaporator, capillary means extending through said conduit and terminating at one end in the lower art of said vessel and at the other end below t e normal liquid level in the evaporator, a suction line communicating with the upper part of said vessel and an ejector tube connecting the lower part of said vessel with the suction line.

9. In a refrigerating system, an evaporator, a suction line connected to said evaporator and having a downwardly enlarged portion outside of the evaporator forming a liquid collecting chamber, capillary means extending from said enlarged portion through the suction line into said evaporator below the normal liquid level therein, and an ejector tube connected from the lower part of said enlarged ortion to the suction line.

10. In a re rigerating system, an evaporator of the flooded type having an opening above the normal liquid level therein, a casing outside the evaporator closing said opening and having a chamber with its upper portion communlcating with the evaporator through'said opening, capillary means extending from said chamber through said opening into the evaporator below the normal liquid level therein, a suction line connected with the upper part of said chamber, and a conduit from the lower part of said chamber to said suction line.

11. The combination with an evaporator DlSCLAIME R 1,838,040.Olyde E. Ploeger, Evansville, Ind. REFRIGERATION. Patent dated December 22, 1931. Disclaimer filed July 27, 1934, by the assignee, Servel, Inc.

Herewith enters this disclaimer to claim 2 thereof, to wit:

2. In a refrigerating system comprising an evaporator, a compressor, a suction line between the evaporator and the compressor, means for returning lubricant from the evaporator to the compressor comprising a housing inserted in said suction line and provided with a lubricant chamber communicating at its upper portion by means of the suction line with the evaporator and compressor and at its lower portion with the suction line, and means for transferring lubricant from the evaporator into said chamber.

[Qflicial Gazette August 21, 1934.] 

